The Elements of Style in Ruby

Slides from my talk at RailsClub.ru 2014

Transcript

1. The Elements of Style in Ruby by Bozhidar I. Batsov
2. Привет!
7. @bbatsov
10. github.com/bbatsov
11. github.com/bbatsov
12. I’m a perfectionist
13. size=2 start=0 c=['Н', 'Н' ,'Н' ,'Н' ,'Н','Н','Н','Н','Н','Н','Н','Н','Н','Н'] code_dictionary=Array.new() begin_size_code_dictionary=Array.new() end_string=String.new() code_dictionary=c.uniq.to_a decode_dictionary=c.uniq.to_a for i in 0...code_dictionary.size begin_size_code_dictionary[i]=i end c.size.times{ if !code_dictionary.include?(c[start,size].to_s)#Comparation code_dictionary.push(c[start,size].to_s.chomp) start=start+(code_dictionary.last.size)/2-1 size=2 else size+=1; end } end_code=Array.new(code_dictionary.size) for i in begin_size_code_dictionary.size...code_dictionary.size end_code[i]=code_dictionary.index(code_dictionary[i].chop.chop)+1 end_string+=code_dictionary[i].chop.chop end govnokod.ru
14. Languages are complex
16. Basic use of a language is relatively easy
17. Correct use of a language is hard
18. Effective use of a language is very hard
21. Use the active voice.
22. My first visit to Moscow will always be remembered by me. lame
23. I shall always remember my first visit to Moscow. legit
24. The word personally is often unnecessary.
25. Personally, I love Ruby.
26. Style guide • curated set of (supposedly) good practices • frees you from making trivial decisions • allows you to focus on the real problems • short and to the point
27. Convention over configuration
28. Style guides are not substitutes for common sense
29. Common sense is not so common…
30. Programs must be written for people to read, and only incidentally for machines to execute. ! — Hal Abelson
31. Similar rules apply for natural and programming languages
33. English
34. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Chapter I
35. LOREM IPSUM DOLOR SIT AMET, CONSECTETUR ADIPISCING ELIT, SED DO EIUSMOD TEMPOR INCIDIDUNT UT LABORE ET DOLORE MAGNA ALIQUA. UT ENIM AD MINIM VENIAM, QUIS NOSTRUD EXERCITATION ULLAMCO LABORIS NISI UT ALIQUIP EX EA COMMODO CONSEQUAT. DUIS AUTE IRURE DOLOR IN REPREHENDERIT IN VOLUPTATE VELIT ESSE CILLUM DOLORE EU FUGIAT NULLA PARIATUR. EXCEPTEUR SINT OCCAECAT CUPIDATAT NON PROIDENT, SUNT IN CULPA QUI OFFICIA DESERUNT MOLLIT ANIM ID EST LABORUM. LOREM IPSUM DOLOR SIT AMET, CONSECTETUR ADIPISCING ELIT, SED DO EIUSMOD TEMPOR INCIDIDUNT UT LABORE ET DOLORE MAGNA ALIQUA. UT ENIM AD MINIM VENIAM, QUIS NOSTRUD EXERCITATION ULLAMCO LABORIS NISI UT ALIQUIP EX EA COMMODO CONSEQUAT. DUIS AUTE IRURE DOLOR IN REPREHENDERIT IN VOLUPTATE VELIT ESSE CILLUM DOLORE EU FUGIAT NULLA PARIATUR. EXCEPTEUR SINT OCCAECAT CUPIDATAT NON PROIDENT, SUNT IN CULPA QUI OFFICIA DESERUNT MOLLIT ANIM ID EST LABORUM. chapter i
36. Русский
37. Эи дуо модо лудуз кэтэро, ты фачтидёе зючкёпит эффикеэнди эжт. Нэ путынт дикырыт кюм. Коммюны пожйдонёюм экз ыюм, омныз мыдиокрым хонэзтатёз вяш йн. Эож ед чент граэкы праэчынт. Эож золэт зэнтынтиаэ рыпримёквуы ат. Дёжкэрэ эрепюят ыам ты, квуым ныморэ глориатюр кюм ед, эа прё долорэж аккюмзан интылльэгэбат. ! Мыа йн граэкйж волютпат интыллыгам. Нам ёудёкабет рыпримёквуы ты, ад прё вёжи экшырки доминг. Дикырыт адипижкй эффякиантур хёз эа. Но кюм жанктюч торквюатоз, эрож рыкючабо мыа нэ, ат вим кибо зкрипторэм. Еллум граэкы рыпудяары ед мыа. Глава 1
38. ЭИ ДУО МОДО ЛУДУЗ КЭТЭРО, ТЫ ФАЧТИДЁЕ ЗЮЧКЁПИТ ЭФФИКЕЭНДИ ЭЖТ. НЭ ПУТЫНТ ДИКЫРЫТ КЮМ. КОММЮНЫ ПОЖЙДОНЁЮМ ЭКЗ ЫЮМ, ОМНЫЗ МЫДИОКРЫМ ХОНЭЗТАТЁЗ ВЯШ ЙН. ЭОЖ ЕД ЧЕНТ ГРАЭКЫ ПРАЭЧЫНТ. ЭОЖ ЗОЛЭТ ЗЭНТЫНТИАЭ РЫПРИМЁКВУЫ АТ. ДЁЖКЭРЭ ЭРЕПЮЯТ ЫАМ ТЫ, КВУЫМ НЫМОРЭ ГЛОРИАТЮР КЮМ ЕД, ЭА ПРЁ ДОЛОРЭЖ АККЮМЗАН ИНТЫЛЛЬЭГЭБАТ. гЛаВа 1 МЫА ЙН ГРАЭКЙЖ ВОЛЮТПАТ ИНТЫЛЛЫГАМ. НАМ ЁУДЁКАБЕТ РЫПРИМЁКВУЫ ТЫ, АД ПРЁ ВЁЖИ ЭКШЫРКИ ДОМИНГ. ДИКЫРЫТ АДИПИЖКЙ ЭФФЯКИАНТУР ХЁЗ ЭА. НО КЮМ ЖАНКТЮЧ ТОРКВЮАТОЗ, ЭРОЖ РЫКЮЧАБО МЫА НЭ, АТ ВИМ КИБО ЗКРИПТОРЭМ. ЕЛЛУМ ГРАЭКЫ РЫПУДЯАРЫ ЕД МЫА.
39. Ruby
40. def some_method do_something do_more do_more end
41. def some_method do_something do_more do_more end
42. sum = 1 + 2 a, b = 1, 2 [1, 2, 3].each { |e| puts e } class FooError < StandardError; end
43. sum=1+2 a,b=1,2 [1,2,3].each{|e|puts e} class FooError<StandardError;end
44. English
45. Form possessive singular of nouns by adding ’s.
46. Bozhidar’s talk ! Batman’s batclaw ! Emacs’s magic
47. Ruby
48. Form predicate method names by adding “?”.
49. even? ! completed? ! batman?
50. English
51. Make the paragraph the unit of composition.
52. Ruby
53. Make the method the unit of composition.
54. English
55. Omit needless words.
56. he is a man who
57. Her story is a strange one.
58. Ruby
59. Omit needless words.
60. if some_condition then # body omitted end
61. def some_method # ... ! return result end
62. English
63. farther ! further
64. Do we have to go much farther?
65. I decided to pursue the subject further.
66. Ruby
67. == === equal? eql?
68. 5 === Fixnum ! Fixnum === 5
69. An Approach To Style
70. Be consistent.
71. Be clear.
72. Русский
73. КПД
74. Коэффициент полезного действия
75. НИИИАТ
76. Научно-исследовательский испытательный институт автомобильной техники
77. Ruby
78. $:
79. $LOAD_PATH
80. $;
81. $FIELD_SEPARATOR
82. $*
83. $ARGV
84. '%d %d' % [20, 10]
85. sprintf('%d %d', 20, 10)
86. sprintf( '%{first} %{second}', first: 20, second: 10 )
87. format('%{first} %{second}', first: 20, second: 10)
88. Ruby is optimised for programmer happiness.
89. Ruby is a huge language
90. Making the “right” choices is hard
91. for i in 1..3 puts "Hello, Moscow!" end
92. 3.times do puts "Hello, Moscow!" end
93. result = [] ! names.each do |word| result << name.upcase end
94. names.map { |name| name.upcase }
95. names.map(&:upcase)
97. The Community Ruby Style Guide
98. A short time ago in an office far, far away…
99. Built on solid foundation
101. With the help of a legion of Ruby hackers
102. With a focus on
103. Simplicity
104. Simplicity is the ultimate sophistication.
105. Clarity
106. The Rules • Clear and concise • Illustrated with example code • Linkable • Neatly organised • Community-approved
107. More than 200 rules!
108. Style evolution
109. { :batman => 'Bruce', :superman => 'Clark', :zorro => 'Diego', :catwoman => 'Selina' }
110. { batman: 'Bruce', superman: 'Clark', zorro: 'Diego', catwoman: 'Selina' }
111. object. one. two. three. four
112. object .one .two .three .four
113. Bikeshedding
114. Style rules that only reflect what is easily discoverable by a trivial examination of the source code seem to me to be the least valuable rules. If the style is not conveying additional information, why bother? ! — Jim Weirich
116. International • Chinese Simplified • Chinese Traditional • French • Japanese • Portuguese • Russian • Spanish • Vietnamese • Korean
117. Rails Style Guide
118. GitHub Ruby Style Guide
119. Inspiration for other style guides
120. The Elements of Ruby Style ? ?
122. def some_method begin x = 5 ! h={:a=>1,:b=>2} if not h raise "Some error occurred" end ! [1, 2, 3].select { |e| e.even? } rescue => e end end
125. Auto-correct
126. def some_method x = 5 ! h = { a: 1, b: 2 } unless h fail 'Some error occurred' end ! [1, 2, 3].select(&:even?) rescue => e end
127. Highly customisable
128. Конец